Rotary oscillating vane pump



Nov. 8, 1949 R. W.YOUNG ROTARY OSCILLATING VANE PUMP s Shee ts-Sheet 1TQai Filed March 20, 1945 INVENTOR. RAYMOND W. YOUNG.

ATTORNEY Nov. 8, 1949 R. w. YOUNG ROTARY OSCILL A'I'ING VANE PUMP 3Sheets-Sheet 2 Filed March 20 1945 INVENTOR. RAYMOND W- YDLINE ATTORNEYNov. 8, 1949 R. w. YOUNG 2,487,685

ROTARY OSCILLATING VANE PUMP Filed March 20, 1945 3 Sheets-Sheet 3INVENTOR. RAY-MONO W- YDLINE.

A'T'TDRNEY Patented Nov. 8, 1949 ROTARY OSCILLATING VANE PUMP Raymond W.Young, Hohokua, N. J., assignmto Wright Aeronautical Corporation, acorporation of New York Application March 20, 1945, Serial No. 588,673

Claims. 1

This invention relates to pumps and is pardisplacement rotarypump.

In the operation of conventional positive-displacement rotary pumps,lubricating oil for the operating parts of the pump becomes intermingledwith the fluid being pumped. This mixture of lubricating oil with thefluid being pumped frequently is quite objectionable in which case it isnecessary to provide some means to separate the lubricating oil from thepumped fluid.

It is an object of this invention to provide a positive-displacementpump, primarily for pumplng gases and vapors, and having a minimumamount of friction and in which it is not necessary to use lubricatingoil within the pump chamber. To this end, and in one form of theinvention, adequate lubrication of the pump-operating parts is obtainedby impregnating one of the rubbing surfaces of said parts with graphite.In a second form of the invention, said pump-operating parts areprovided with oil-lubricated guide portions disposed outside the pumpchamber and against which the pump-reaction forces are exerted.

Specifically, the invention comprises a pump having a rotoreccentrically-mounted within the pump chamber and having a plurality ofvanes pivotally mounted at their inner edges about axes disposed aroundthe outer surface of said rotor. Said vanes extends outwardly from saidrotor and suitable spring means are provided which, together with thecentrifugal force acting on the vanes, urges the outer edges of saidvanes about their pivot axes toward contact with the inner wall of saidpump chamber. With this construction, during pump operation each vaneonly oscillates relative to the pump rotor so that the frictiontherebetween is quite small. In addition, said vanes not only act as thefluid-displacing means of the pump but also provide for pump pressurerelief at a pressure determined by the spring forces acting on thevanes.

Other objects of this invention will become apparent upon reading theannexed detailed description in connection with the drawing in which:

Figure l is an axial section through a pump embodying the invention,said section being taken along line |--i of Figure 2;

Figure 2 is a sectional view taken along line 2--2 of Figure 1;

Figure 2A is an enlarged sectional view of a modified portion of Figure2;

Figures 3 and 4 are enlarged side and end views of one of thevane-operating springs illustrated in Figure 1;

Figure 5 is a view taken along line 5-5 of Figure 1;

Figure 6 is a view taken along line 6-6 of Figure 2;

Figure 7 is an enlarged perspective view of one of the pump vanes;

Figure 8 is an axial section through a modified pump and taken alongline 8-8 of Figure 9;

Figure 9 is a broken sectional view taken along line 9-9 of Figure 8;and

Figure 10 is a fragmentary view of a modified pump rotor construction.

Referring first to Figures 1 to 7, particularly to Figures 1 and 2, apump I0 is provided with a pump housing having a body portion [2 and endmembers l4 and I6 secured thereto. A cylindrical sleeve 18, fittedwithin said body portion, defines a chamber 20 therewithin having anaxis indicated at 22 in Figure 2. The pump body portion I2 is providedwith inlet and outlet ports 24 and 26 and conduits 28 and 30 are adaptedto be connected to said body portion in alinement with said inlet andoutlet ports respectively. The sleeve I8 is provided with a plurality ofslots 32 and 34 at the inlet and outlet ports respectively, therebyestablishing communication between said inlet and outlet ports and thepump chamber 20. Obviously, the sleeve I8 could be dispensed with inwhich case the slots 32 and 34 would be formed directly in the pump bodyportion.

The pump end members [4 and I6 provide opposed alined bearings 36 and 38having an axis, indicated at 40 on Figure 2, offset from the axis 22 ofthe pump chamber 20. A pump rotor member 42 is disposed within the pumpchamber 20 and said rotor member is piloted on radiallyextending flanges44 and 46 on shaft members 48 and 50 journaled within bearings 36 and 38respectively. The shaft member 48 extends beyond the pump housing and isprovided with splines 52 to which suitable means (not shown) for drivingthe pump is adapted to be connected. Annular plate members 54 and 56 aresuitably secured to the shaft flanges 44 and 46 respectively, forexample by rivets 58, and the rotor member 42 is secured between saidplate members by screws 60. Each annular plate member is provided withan equal plurality of bearings 62 within which the pump vanes 64 arejournaled, as hereinafter described.

The construction of each pump vane 64 is vanes 64 and these vane partsare secured together b welding or brazing.

A hollow longitudinally-slotted tube 10 is fitted over the elongatedcylindrical rib 68 at the outer edge of each vane. Each tube 10 has alongitudinal slot 12 and an internal bore 14 such that it may besecurely fitted over the outer rib edges 68 of the vane elements bysliding this tube lengthwise over said rib edges. Preferably, each tube10 comprises a suitable graphite-impregnated plastic. Such plastics arecommercially available, e. g. under trade names Textolite or Synthane.In this way, each vane element is provided with a graphite-impregnatedplastic tip which is readily replaceable. The use of plastic materialfor the pump vane tips is particularly suitable in that if any foreignmatter should become trapped between a pump vane 64 and the adjacentcylindrical wall of the chamber 20, this foreign matter will tend toimbed itself within the plastic material instead of scratching this wallof the pump chamber. The addition of the graphite helps lubricate theengaging surfaces of the vanes 64 and the cylindrical wall of the pumpchamber .to reduce the friction therebetween.

Each vane shaft portion 66 projects beyond each end of the body portionof its associated vane and these projecting portions are journaledwithin opposed bearings 62 carried by the annular plate members 54 and56 and the body portion of the vanes extends between the end walls ofthe cylindrical pump chamber 20. The pump rotor member 42 is providedwith a number of equally-spaced radially-extending flanges 16 equal tothe number of pump vanes 64. One corner 18, defined by each of saidflanges l6 and the adjacent surface of the rotor member 42, is machinedto a cylindrical curvature similar to the curvature of the vane shaftportions 66 to provide a close fit with said portions. Thus, thebearings 62 carried by the annular plate members 54 and 56 have aspacing similar to the spacing of the radial flanges 76 such that, whenthe projecting ends ,of the vane shaft portions 66 are journaled withinthe bearings 62, the vane shaft portions are received with a minimum ofclearance within said cylindrical corners l8. Actually, annular plate 54and/or 56 with their bearings 62 may be used as a fixture for accuratelylocating and machining the corners 78.

The outer edges 10 of the vanes 64 are adapted to engage the interiorsurface of the pump chamber 20 such that, relative to the direction ofrotation of the rotor member 42, the outer edges 10 of the vanes trailtheir inner edges 66. A suitable helical spring 80 is provided betweenthe projecting ends of each vane shaft portion 66 and the adjacentannular plates 54 and 56 which springs, together with the centrifugalforce acting on each vane, rotatively urge the outer vane edges 10 intoengagement with the interior surface of the pump chamber 20.

With this construction, when a drive is applied to the shaft 48, in adirection indicated by the arrow in Figure 2, the vanes are caused torotate with said rotor and the springs 80, together with the centrifugalforce acting on the vanes 64, maintain the outer edges of the vanes incontact with the interior cylindrical surface of the pump chamber 20.Because of the eccentricity between the axes of the rotor member 42 andpump chamber 20, the vanes 64 oscillate relative to the rotor duringpump operation as indicated in Figure 2. In this way, as the pump rotorand vanes rotate, fluid is trapped between the vanes and, because of thepivotal movement of the vanes about the bearings 62, the space betweenadjacent vanes becomes smaller as they approach the pump outlet port 26thereby increasing the fluid pressure P to this outlet port. Thegraphite-impregnated tubes I0, at the outer edges of the vanes, provideadequate lubrication between the vanes and the interior of the pumpchamber 20. Also, since the vanes 64 only oscillate relative to therotor member 42, there is relatively-little friction therebetween.

One end of each of the springs is anchored to a vane shaft portion 66 ina bore 61 extending therethrough while the other end of each spring isadapted to be anchored in any one of a plural ity of recesses 82 in theassociated annular plate 54 or 56, as seen in Figures 3 and 4. In thisway, the spring force on each vane may be adjusted. This spring force,together with the centrifugal force acting on each vane, determines themaximum pump discharge pressure since, if the pump pressure against thevanes exceeds a certain value, it will rotate the vanes against theirsprings 80 and the centrifugal force acting on the vanes, therebyproviding clearance between the outer vane edges 10 and adjacent wall ofthe pump chamber 26 to relieve pump pressure. Thus, for a given pumpspeed, the maximum pump discharge pressure can be varied by adjustmentof the springs 80. A suitable removable plug 84 is provided at each endof the pump housing to provide easy access to the springs 80. Only onesuch plug is necessary at each end of the pump housing since the pumprotor 42 can be rotated to successively aline the vane springs 80therewith.

With the aforedescribed construction, no lubricating oil is necessarywithin the pump chamber 26. The graphite-impregnated plastic tip alongthe outer edge of each vane provides suflicient lubrication to take careof the contact between the outer edge of each vane and the adjacentsurface of the pump chamber 20. If the pump is operated at the maximumdischarge pressure permitted by the spring and centrifugal forces on thevanes 64, then there will be substantially no contact pressure betweenthe outer edge of each vane and the adjacent cylindrical wall of thepump chamber 20 for a portion of each revolution 01 each vane in thevicinity of the pump outlet port 26 thereby further reducing the amountof friction between the outer edge of each vane and the adjacentcylindrical wall of the pump chamber 20.

A suitable lubricant is provided for the pump bearings 48 and 50. Inorder to prevent this lubricant from finding its way into the pumpchamber 20, each end member I4 and I6 is provided with an annular groove66 within which a seal ring 88 is disposed. Each seal ring 88 is urgedinto engagement with the pump rotor by suitable spring means 90. Therings 88 may be of any suitable material such as carbon or othersuitable seal ring material. Obviously, if desired or necessary,suitable seal means may also be provided between the outer surface ofthe pump rotor annular plates 54 and 56 and the adjacent end members I4and I6 respectively.

The vanes 64 preferably have a curvature such that they are inwardlyconcave in. order to reduce the clearance volume of the pump. Thus, asillustrated in Figure 2, because of this vane curvature, the clearancevolume between the adjacent wall of the pump chamber and a vane 64 isquite small as the vane rotates beyond the pump outlet port 26.Obviously, this clearance volume may be further reduced by providing anabrupt and inwardly-concave curvature for each vane 64 at its junctionwith its inner edge or shaft portion 66.

Referring now to Figure 8 and 9, which illustrate a modified form of theinvention, a pump H0 is provided with a body portion H2 and an endmember H4 at one end thereof. The pump body portion IIZ provides acylindrical pump chamber I I6 as in Figures 1 to '7 but in themodification of Figures 8 and 9, the end member H4 is separated from thebody portion II2 by an annular partition IIB thereby defining an endchamber I20. Preferably, the end chamber I20 is co-axial with and has adiameter equal to the diameter of the pump chamber HE. A pump rotormember I22 is suitably secured to a shaft portion I24 which, in turn, isjournaled within the bearing I26 carried by the end member H4. The axisof the rotor member I22 is eccentric relative to the axis of the pumpchamber IIB as best seen in Figure 9. Suitable seal rings I20 areprovided between an annular radial flange I29 on the pump shaft I24 andthe partition II8 thereby providing a seal between the pump chamber H6and the end chamber I20. The opposite end of the pump from the endmember II4 has not been illustrated but preferably is substantially thesame as the construction of Figures 1 to '7.

Pump vanes I30 are journaled about the pump rotor i22 as in Figures 1 to'7 except inFigures 8 and 9, one end of the shaft portion I32 at theinner edge of each pump vane is extended into the end chamber I20 and aguide vane I34 is keyed or otherwise secured thereto. Adjustable helicalspring means I30 are provided as in Figures 1 to 7 for urging each vaneI30 toward engagement with theadjacent wall of the pump chamber II6. Inaddition, each spring means I36 also urges each guide vane I34 intoengagement with the adjacent surface of the end chamber I20.

The arrangement is such that each guide vane contacts the cylindricalsurface or track of its end chamber I20 to relieve its associated pumpvane I30 of actual contact pressure with the surface of the pump chamberH6. With this construction, there is little or no friction between thepump vanes I30 and the interior of the pump chamber II6. In the endchamber I20, the friction and wear between the guide vanes I34 and theend chamber I20 may be reduced by the introduction of lubricating oiltherein-for example, from the pump bearing I26. The presence oflubricating oil in the end chamber I20 is not objectionable since thechamber I20 is sealed from the pump chamber IIB by rings I28. Inaddition, the guide vanes I34 and pump vanes I30 may be provided withgraphite-impregnated plastic tubes I38 and I over their outer edges asin Figures 1 to 7 thereby further reducing the pump friction. The vanesI30 and I34 preferably have the same shape, but the plastic tubes I40have a slightly larger outer diameter than the tubes I38 whereby thevanes I30 are relieved of actual contact pressure with the cylindricalsurface of the pump chamber I I6. However, the clearance between theouter edges of vanes I30 and the cylindrical surface of the pump chamberI I6 is quite small.

The provision of the graphite-impregnated plastic tubes I38 at the outeredges of vanes I30 is in the nature of a safety feature to prevent unduefriction between the vanes I30 and the pump chamber H6 in case there isappreciable wear of the tubes I40 at the outer edges of guide vanes I34.The guide vanes I34 are also provided with stiffening webs I42. Theconstruction of Figures 8 and 9 is otherwise similar to the structure ofFigures 1 to '7. At this point it should be noted that it is notnecessary that chambers I I0 and I20 be of the same diameter.

In both of the aforedescribed modifications there is only a small amountof relative motion between the inner edge of each vane and the adjacentpump rotor. However, if desired, the pump friction may be furtherreduced by providing a graphite-impregnated slotted plastic tube overthe inner shaft portion 66 or I32 of each vane similar to the tubes 10or I38 provided at their outer edges. Such a construction is illustratedin Figure 2A in which a graphite-impregnated longitudinally-slottedplastic tube I40 is fitted over the inner shaft portion 08 of a vane 64.Figure 10 illustrates a slight modification of this construction inwhich a graphite-impregnated plastic tube I50 is fitted within slottedcylindrical bores within the pump rotor I52 in alinement with vanebearings at the ends of the pump rotor. Each tube I50 islongitudinallyslotted as indicated at I54, whereby the inner edge orshaft portion 66 or I32 of each vane 64 or I30 may be assembledtherewith by sliding lengthwise therein. Also, the width of each slotI54 is sufficient to accommodate the angular movement of the associatedvane relative to the pump rotor.

The aforedescribed modifications provide a positive-displacement rotarypump especially suitable for pumping gases or vapors and in which nolubricating oil is required in the pump chamber and in which the pumpoperates with a minimum of friction. ,In addition, in each modificationthe fluid-displacing means or vanes of the pump also act as a pressurerelief valve.

While I have described my invention in detail I in its present preferredembodiment, it will be obvious to those skilled in the art, afterunderstanding my invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Iaim in the appended claims to cover all such modifications.

I claim as my invention:

l. A pump vane having a cylindrical rib along one edge thereof, and alongitudinally-slotted graphite-impregnated plastic tube fitted oversaid rib, the slot in said tube being arranged to permit said tube to beslid longitudinally over said rib.

2. A pump comprising a housing having a cylindrical chamber therewithinand having fluid inlet and outlet parts communicating with said chamber,a pump rotor member eccentrically mounted within said chamber, aplurality of vane members pivotally mounted about the outer periphery ofsaid rotor member and extending outwardly therefrom toward thecylindrical surface of said chamber for pumping fluid from said inletport to said outlet port upon rotation of said rotor member, each orsaid vane members having a substantially-cylindrical rib along its innerand outer edges and a longitudinally-slotted graphite-impregnated tubedisposed about said cylindrical ribs along the inner and outer edges ofsaid vane members.

3. A pump vane having a longitudinal rib along one edge thereof, and alongitudinally-slotted tube fitted over said rib, the slot in said tubebeing arranged to permit said tube to .ie slid longitudinally over saidrib.

4. A pump comprising a housing having a first chamber therein with fluidinlet and outlet ports communicating with said chamber, and a secondchamber within said housing co-axial with but out of communication withsaid first chamber; a pump rotor eccentrically mounted within said firstchamber; a. piurality of vanes pivotally carried by and extendingoutwardly from said rotor for pumping fluid. from said inlet port tosaid outlet port upon rotation of said rotor; a plurality of guidemembers in said second chamber each secured to' one of said vanes forjoint pivotal movement of each vane and its guide member about the pivotaxis of said vane; said guide members extending into engagement with theouter wall of said second chamber for enforcing pivotal movement of saidguide members and their vanes in response to rotation of said rotor suchthat in each position of a guide member the outer end of its associatedvane is disposed in close proximity to the outer wall of said firstchamber,

5. A pump comprising a, housing having a first chamber therein withfluid inlet and outlet ports communicating with said chamber, and asecond chamber within said housing co-axial with and axially spaced fromsaid first chamber but out of communication with said first chamber; apump rotor eccentrically mounted within said first chamber; a pluralityof vanes pivotally carried by and extending outwardly from said rotorfor pumping fluid from said inlet port to said outlet port upon rotationof said rotor; at pluraiity of guide members in said second chamber eachsecured to one of said vanes for Joint pivotal movement of each vane andits guide member about the pivot axis of said vane; said guide membersextending into engagement with the outer wall of said second chamber forenforcing pivotal movement of said guide members and their vanes inresponse to rotation of said rotor such that in each position of a guidemember the outer end of its associated vane is disposed in closeproximity-to the outer wall of said first chamber.

RAYMOND W. YOUNG.

REFERENCES CITED The following references are of record in the file ofthis patent:

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